Brendan wrote:
Sure, everything can be a whole lot faster, as long as you never actually produce a chip and find out how badly it performs on real software. I'm sure Itanium looked good on paper too.
Of course there's also the other problem - as soon as you break compatibility you're stuck in "no man's land" where nobody wants to write software for it because there's no market share, and there's no market share because there's no software for it; and where the price is high because the volume is low and you can't afford the latest manufacturing process so "performance per watt" suffers, making the whole "catch 22" worse;
Yes, this is definitely possible and happens, but we're talking about the future end of Moore's law here. While it does look like a huge challenge to complete with x86, it's even less likely that everyone will just permanently give up when the limits of x86's design are reached, if there turns out to be anything better at all.
Further, I honestly don't think Itanium is all that relevant in this context. It made a lot of obvious-in-retrospect mistakes that have nothing fundamentally to do with the techniques it tried to champion, and because of its failure there hasn't been a lot of exploration of alternative implementations since. As I'm sure you remember, a lot of us got excited about the Mill CPU when it was announced precisely because it presented some concrete possibilities for those alternative solutions. Who knows if it'll work, but it's not a sure-fire failure either.
Brendan wrote:
There's a reason that every single architecture that's ever gone "head to head" against Intel/80x86 has died.
The way to do this (before my far-future prediction) is not to go head-to-head with x86. Like embryo mentioned, ARM is getting pretty big by powering mobile devices, something x86 is awful at. Another example of what could be done is GPUs, which don't even tend to have a defined macroarchitecture. Also, every few years we get a new generation of game consoles, where it's pretty much irrelevant what architecture you use and the designers just want lower cost (and for mobile ones, power usage). If you can find a niche where it's easy to switch out CPUs
and offer some tangible benefit for that niche over x86 in performance/watt/$, there's a lot more precedent for success.